There is need for improved resins for advanced, high performance composites for aircraft, space and consumer applications. Diaminodiphenyl sulfone (DDS) has been added to high temperature epoxy formulations to provide humidity resistance. However, the DDS-epoxy reaction is extremely slow and the material never cures completely. The most widely utilized latent catalysts for promoting the reaction of DDS with epoxies are BF.sub.3 -amine complexes. However, the BF.sub.3 -complex is a much better accelerator of the epoxy to epoxy reaction and when used in conjunction with DDS, because of the sluggishness of the DDS-epoxy reaction, a substantial portion of the DDS remains unreacted, acting as a plasticizer in the cured product.
Imidazoles and especially alkylated imidazoles are known to provide high temperature epoxies with excellent properties. However, these formulations gel in minutes and do not provide any latency.